1. Field of the Invention
This invention relates to a device for opening and closing a reed switch. The device has a reed switch operated by a change of magnetic flux and a magnet means for operating the reed switch movably disposed relative to and adjacent to the reed switch.
2. Description of the Prior Art
In the conventional device for opening and closing a reed switch, a sensitive operation which can be put into practical use cannot be expected where one reed switch is opened and closed by using one magnet means composed of one magnet having N and S poles. The reasons this is so are as follows:
As will later be described in detail with reference to the drawings, the periphery of the magnetic force area of the magnet means is unstable and therefore the working distance of the magnet means must be rather large in order to satisfactorily operate the reed switch. On the other hand, the working distance of the magnet means is required to be as short as possible for operational reasons. Generally it has been difficult to simultaneously satisfy the above two contradictory conditions.
In order to overcome such disadvantages of the above-mentioned type device, it has been attempted to realize a sensitive operation of the reed switch, for example, by variously arranging three poles (N,S,N) or four poles (N,S,N,S) of magnets to thereby change the distribution of the magnetic flux or the direction of a part of the lines of magnetic force. However, such a device having magnet means composed of a combination of three or four poles of magnets and one reed switch operated by the magnet means is very complicated in construction. It also has the disadvantage that, due to the mutual interference of the lines of magnetic force, unstable factors are increased which has the possibility of deteriorating the sensitive opening and closing operations of the reed switch. In cases where a number of such devices are arranged in parallel as in the case of an electronic computer, the above-mentioned unfavorable characteristics can be quite detrimental.